Dietary Fiber Health Benefits

 Abstract

Background: Dietary fibre consists of non-digestible forms of carbohydrate, usually as polysaccharides that originate from plant-based foods. Over recent decades, our diet within Westernised societies has changed radically from that of our hominid ancestors, 

with implications for our co-evolved gut microbiota. 

This includes increased ingestion of ultra-processed foods that are typically impoverished of dietary fibre, and associated reduction in the intake of fibre-replete plant-based foods. 

Over recent decades, there has been a transformation in our understanding of the health benefits of dietary fibre. 

Objective: To explore the current medical literature on the health benefits of dietary fibre, with a focus on overall metabolic health. 

Data Sources: We performed a narrative review, based on relevant articles written in English from a PubMed search, using the terms ‘dietary fibre and metabolic health’. 

Results: In the Western world, our diets are impoverished of fibre. Dietary fibre intake associates with overall metabolic health (through key pathways that include insulin sensitivity) and a variety of other pathologies that include

 cardiovascular disease, colonic health, gut motility and risk for colorectal carcinoma. Dietary fibre intake also correlates with mortality. The gut microflora functions as an important mediator of the beneficial effects of dietary fibre, including the regulation of appetite, metabolic processes and chronic inflammatory pathways. 

Conclusions: 

Multiple factors contribute to our fibre-impoverished modern diet. Given the plethora of scientific evidence that corroborate the multiple and varied health benefits of dietary fibre, and the risks associated with a diet that lacks fibre, the optimization of fibre within our diets represents an important public health strategy to improve both metabolic and overall health. If implemented successfully, this strategy would likely result in substantial future health benefits for the population

Introduction

In our modern-day, 21st century world, chronic diseases predominate. Underlying much of this chronic disease burden are pathological pathways that implicate inflammation and metabolic dysfunction (including insulin resistance).

 In recent decades, much evidence supports an important role for our lifestyles in the development of such inflammatory and dysmetabolic processes, such as, for example, our sleep, physical activity and diet. 

Such lifestyle factors also contribute towards

 weight gain and obesity, which represent a particularly important contributor to chronic ill health, including >50 medical conditions (such as type 2 diabetes mellitus (T2D), dyslipidaemia, hypertension, obstructive sleep apnoea and cardiovascular disease). Global obesity prevalence has tripled over the last half century, with current rates of obesity and overweight affecting 650 million and 1.9 billion people respectively [1,2]. In addition to multi-morbidity, obesity also associates with premature mortality as evidenced by data from the Framingham Heart Study [3]. Obesity has a substantial and diverse impact on

 psycho-social functioning [4], work productivity [5] and global healthcare expenditure [6].

Important advances have been made in recent years regarding our understanding of appetite and metabolic regulation [7], 

metabolic surgical [8] and medical therapeutic approaches to obesity [9]. However, regardless of therapeutic choice for obesity management, ultimately, weight loss stems from behavioural change at an individual level [10]. At the heart of such behavioural change lies dietary modification. Despite this insight, however, it is remarkable how little we know about our diet. Nutritional studies are notoriously difficult to execute and interpret for a variety of reasons that include self-reporting of food intake [11], multiple confounding factors (such as variations in genetic, metabolic and gut microbial factors), impaired compliance with dietary changes and the difficulties associated with the study of macronutrient changes in isolation (with inevitable consequences for other ingested macronutrients). All of these factors conspire to create much uncertainty regarding the optimal dietary needs for the individual. To compound this uncertainty, the popular media is littered with an effusion of fad diets with phony promises of long-lasting weight loss and health, often based on little if any proper scientific evidence and rigour. It is little wonder that patients and many healthcare professionals are confused about the optimal diet to follow and advocate. In response, esteemed societies and governments around the world have tended to offer generic dietary advice on a population-based level. For decades, much focus has rested with advice to adopt a ‘low-fat’ diet [12] that, more recently, has shifted towards a ‘low-carbohydrate’ diet [13] (with associated examples of ‘sugar-tax’ and limitations on food advertising for children).

In this narrative review, we focus on dietary fibre, a macronutrient that has perhaps not received as much attention as its more attractive counterparts, fat and carbohydrates. Our objective was to explore the current medical literature on the health benefits of dietary fibre, with a focus on overall metabolic health but also on gut motility, gut microbiota, chronic inflammation, mental health, cardiovascular disease, colorectal carcinoma and mortality. We also provide a suggested strategy for how we can optimise dietary fibre intake within the population in the context of our fibre-impoverished modern-day world.

Nutrients. 2020 Oct 21;12(10):3209. doi: 10.3390/nu12103209

The Health Benefits of Dietary Fibre

Thomas M Barber 1,2,3,*, Stefan Kabisch 4,5, Andreas F H Pfeiffer 4,5,6, Martin O Weickert 1,2,3,7,*